The present invention relates to an improved core chuck for hollow roll cores, particularly as used with rolls of packaging films, paper and other web material, but not limited thereto.
In the paper, plastic, printing and related industries, paper, plastic or other sheet material in web form is often handled in the form of rolls of the material wound onto hollow paperboard, fiber or plastic cores. Although some cores may have a notch or key opening in one or both ends for engagement by a key. Such a notch or key opening is not required for chucks which fit into and engage the hollow interior of the core. In any case, cores secured in a core can be suitably driven for winding or unwinding the material. With keyed web cores, often core ends are damaged or key slots are mutilated which renders a key of a core chuck unsatisfactory for keeping the core firmly secured for winding and unwinding. The core chuck of the present invention does not rely on the presence or absence of a notch in the core.
Different keyless chuck expedients have been proposed including expanding chucks, tapered chucks with fluted surfaces and chucks with internal core restraints which tilt, expand or extend into position. However, these expedients have provided core chucks that are quite expensive, difficult to maintain and use, and often unsatisfactory in performance.
Some of the prior art core chucks are exemplified in the following U.S. Pat. Nos. 1,402,060; 2,922,592; 3,368,769; 3,704,837; and 4,045,038.
The above noted U.S. Pat. Nos. 1,402,060, 2,922,592 and 3,704,837 each work on the principle whereby internal core restraining devices are forced into position automatically by mechanical action as the core is inserted on the chuck, while prior U.S. Pat. No. 3,368,769 uses a floating key arrangement for accommodating different sized cores. Later U.S. Pat. No. 4,045,038 utilizes chuck dogs that are normally spring biased into a retracted condition, but which can be engaged into the hollow core by a separate mechanical action not inherent with the placing of the core on the chuck.
In contrast, it will be seen that the core chuck of the present invention provides at least one elongated element residing in an angularly situated hole extending into the core enclosed chuck portion and which can be manipulated to extend outside the chuck periphery to engage positively with the core interior. Thus rotational unity between chuck and core is secured by a simple and reliable mechanism overcoming disadvantages of the prior chuck devices. The core of the present invention is particularly useful with damaged or poorly made cores, and commendably satisfies a need for a simple, easy-to-employ device of rugged construction.